Variable speed drive



April 21, 1942. L. ZUPAN r 2,280,182

' I VARIABLE SPEED DRIVE 7 Filed Aug. 3, 1940 2 Sheets- Sheet 1 Aeo Zupan pwvlawwl 1W April 21, 1942.

ZUPAN 2,280,182 VARIABLE SPEED-DRIVE Fi led Aug. 3,1940 ,2 Sheets-Sheet 2 460 Zuparz r '(flT-romtzys Patented Apr. 21, 1942" .LeoZupan. Chicago, 111....assignor to Sheldon Machine Company, lnc fihicagoyllh, a corporation of Illinois Application fAugust3, 1940,. Serial No. 350,524

"1 Claims; Jl.74--217) The present invention relates to variable speed drives, andhas particular reference to a new and improved underdrivefor lathes.

One of the objects of the present invention. is to provide a novel underneath motor drive for lathes which is fully enclosed within a cabinet leg and which may be adjusted for different speeds by means of hand actuators operable from the exterior of the leg, thereby permitting speed changes with ease, speed and safety.

Another object is to provide a new andimproved underneath motor drive whichis simple,

is a headstock 5 in which a spindle 6 is suitably journaled. The spindle 6 may be connected through any conventional means to drive a lead screw 1 extending. along and journaled at opposite ends on the front of the base I. A tool slide 8. is suitably mounted on the bed I. and

compact and efficient. in construction and in which drive pulleys are not subjected jectionable degree of friction. l

Further objects andadvantages will. become apparent as the description proceeds.

In the accompanyingdrawings, p .Figure 1 is a view of a latheprovided with. an underdrive embodyingthefeatures of invention. l l

to an ob- Fig. 2 is a transverse vertical sectional view through the base of the lathe taken, along line 22 of Fig. l and side elevation; u r f Fig. 3 is a fragmentary longitudinal vertical sectional View through the base taken along line showing the underdrive in 3-3 of Fig. 2 and showing the underdrive in v front elevation. t p l l l Fig. 4 is a fragmentary sectional view on an enlarged scale] of the main clutch shaft taken substantially along line 4-4 of Fig. 3.

Fig. 5 is a transverse sectional view taken along line 5--5 of Fig. 4.

Fig. 6 is a fragmentary sectional view taken along line 6-6 of Fig. t 1 t I While the invention is susceptible of various modifications and alternative constructional have shown in the drawings and will herein, describe in detailthe preferred embodiment, but itis to be understood that I do not thereby intend to limit the invention to the specific form.

disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and Scope of the invention as expressed in the appended claims.

The variable speed drive [constituting the exemplary embodiment ofthe invention is incorporatedfor purposes of. illustration. asan underdrive for a screw lathe such as illustratedin Fig. .1. ,The lathe comprises a horizontal bed I supported at one end by a leg 2 andv at the other end by a hollow closed pedestal leg 3 having a cover or door 4 in the ifront. .Mountedyon.

adapted to be traversed therealong by power rotation of the lead screw 1.

The underdrive is enclosed within the pedestal leg 3 and connected to drive the spindle 6.. Referring to Figs. 2 and 3, the underdrive. comprises a mounting bracket 9 having a top plate I anda depending vertical leg H at the rear. Projecting upwardly'from the rear edge of the top plate II] are two spaced aligned ears l2 which are rotatably suspended from suitably sealed bearings I3 on a pivot shaft l4 supported in bosses I on the rear wall of the pedestal leg 3. These bearings 13 are constructed to permit grease gun lubrication. The front edge of the top plate is suitably supported from the top of the pedestal leg '3 for pivotal adjustment about the. shaft I4. In the present instance, a clevis I6 is bolted to the top wall of the pedestal leg 3.

. A vertical eye bolt I1 is secured at its upper end to. the clevis l6 by means of a pivot bolt [8 for free swinging movement transversely of the shaft I l. The lower threaded end of the bolt ll extends through an open slot [9 in the front edge of the top 'plate lll. Two nuts are adjustably threaded onto the bolt I! and are adapted to be turned into engagement with opposite faces of the top plate [0 to clamp the latter in position of adjustment. I

Formed on the top of the plate It are two spaced bosses 2|. A drive shaft 22 is journaled at opposite ends in: bearings 23 supported in the bosses 2| adapted for grease gun lubrication. The shaft 22 extends parallel to the shaft [4 and has secured thereto a double V pulley 24. Two V belts serve to connect the pulley 24 to a similar pulley (not shown) secured to the spindle 6 within the headstock 5. By loosening one of the nuts 20 and tightening the other nut 2|], the top plate 10 may be adjusted upwardly or down.- wardly as required to place the belts 25 under proper'tension.

Mounted on the vertical leg H- of the bracket 9 is an intermediate bracket or plate 21. In the presentinstance, the plate 21 has spaced rearwardly extending ears 28 interfitting with marginal vertical flanges 29 on the depending leg H. The cars 28 are pinned to a. pivot shaftior the bed I substantially over the pedestal. leg 3 55. r d 30 extending through the an s 29 so as to provide a pivotal support for the intermediate bracket or plate 21.

Means is provided for angularly adjusting the plate 21, and in the present instance this means comprises an upwardly extending bolt 3|. The lower end of the bolt 3| has a ball and socket connection 32 with the plate 21, and the upper end of the bolt extends through a slot 33 in the top plate In. Nuts 34, threaded onto the bolt 3| at opposite faces of the top plate In, afford means whereby the plate 21 may be adjusted and supported in different relative angular positions. I

Formed on the underside of the intermediate plate 21 adjacent the side edges are two depending bearing brackets 35 (see Fig. 9:) adapted to support a main tubular clutch shaft 31 extending parallel to the shafts l4 and 22. The shaft 31 is supported by suitable roller bearings 38 opposite ends of the bore 68 and are pressed outwardly by an interposed coiled compression spring 63. The balls are thus urged outwardly of the ends of the bore 68 for engagement selectively with three different sets of recesses 64, 65 and 66 formed in longitudinally spaced relation inside the shaft 31. A screw plug 61 is threaded into the outer end of the nut 49 to close the outer end of the shaft 31 so that the clutch space.

is fully enclosed. The pulley 44 is provided with To provide means for shifting the rod 36, a

I pin169 extends through and is secured in a which are sealed against leakage and which are 1 adapted to be lubricated through grease gun fit tings 39. A shifter rod 36 extends slidably in one end f the shaft 31. Rotatable on the right end of the shaft 31 and disposed in bearing engagement through an antifriction washer 48 against the outer end of the contiguous bearing bracket 35 is a sleeve 4| fitting tightly within and secured as by means of keys 42 to the hub 43 of a V pulley 44. Similarly disposed on the shaft 31 outwardly of the sleeve 4|, is'a coaxial sleeve 45 which is tightly fitted within and secured as by means of a key 46 to the hub 41 of a larger V pulley 48.- A nut 49 is threaded onto the outer end of the shaft 31 and coacts with the bearing lug 35 'to confine the sleeves 4| and 45 together with the pulleys 44 and 48 in assembledrelation. A suitable antifriction washer 50 may be interposed between and in bearing engagement with the pulleys 44 and 48.

Suitable clutch means is provided for connecting the pulleys 44 and48selectivelyto the shaft 31.. In itspreferred form, this clutch means comprises a clutch pin extending through and projecting from .opposite, ends of .a transverse bore 52 in the rod 36. Preferably, the pin 5| is suitably secured in centered position :within. the 7 rod 36,, and to this end two set screws 53 .are threaded into opposite ends of .aparallel transverse bore 54 in the. rod and have tapered inner ends in wedging engagement with, a ,ball 55 tightly seated in av-shaped notch 56in one side of the pin 5| The projecting ends of the pin 5| extend slidably through diametrically opposed longitudinal slots 51 formed in the outer end of the shaft 31 and are adapted upon axialfrnovement of the rod 36 in opposite directionsto engage 'selectively in diametrically opposed notches 58 and 59 formed in the adjacent ends of the sleeves 4| and 45. It will be seen that when the rod 36 is in one extreme position of adjustment, the pin 5| will engage in the notches or recesses 58 to connect the small pulley 44 for rotation with the shaft 31. When the rod 36 is adjusted into the other extreme position, the pin 5| will engage in the notches or recesses 59 to connect the relatively large pulley 48 for rotation with the shaft 31. In the neutral or intermediate position of the rod- 36, the pin 5| will be disposed between and clear of the sleeves 4| and 45 so that neither v pulley will be connected.

Suitable detent means is provided'for securing the rod 36 yieldably in its three selective positions of adjustment. This means comprises a transverse bore 68 formed in the rod 36 adjacent its outer end and intersecting an axial bore 6|. Two balldetents 62 are disposed respectively in transverse bore 18 formed in the rod 36 at a point between the bearing brackets 35. The projecting ends of the pin 69 extend slidably through two diametrically opposed longitudinal slots 1| formed'in the shaft 31 and are suitably secured as by means of a set screw 12 to a clutch collar 13 having a peripheral groove 14. A clutch yoke 15 engages in thegroove 14 of the collar 13 and is keyed to the rear end of a shaft 16 journaled in the intermediateplate 21. The shaft 16 projects forwardly from the plate 21 through an opening 11in the front cover or door 4 of the pedestal leg 3, and is provided externally of the leg with a suitable hand lever 18. v

The pulley 44'is connected through a V belt 19 to a relatively large pulley keyed to the shaft 22. Similarly, the pulley 48 is connected through a V belt 8| to a relatively small pulley 82 also keyed to the shaft 22. Consequently, by appropriate manipulation of the hand lever 18, the shaft 31 may be connected at either of two speeds to the shaft 22, or may be disconnected to interrupt the drive to the spindle.

A similar clutch arrangement is provided .on the other end of the shaft 31 for selectively connecting either of twopulleys 83 and 84. These pulleyshave hubs 85 and 86, respectively, separated by an antifriction washer 81 and are confined on the shaft 31 against the bearing bracket 35'byla nut 88. Suitable antifriction washers 89 and 98 are interposed respectively between the bearing bracket 35 and the hub 86, and the hub 85 and the nut 88. Two clutch sleeves 9| and 92 are secured as by means of keys 93 in the hubs 85 and 86, respectively, and are formed in their adjacent ends with diametrically'opposed notches or recesses 94 and 95, respectively. A shifter rod 96- extends slidably in the tubular shaft 31 and carries a transverse pin 91 secured in position by a ball 98 in a manner similar to the pin 5|. The projecting ends of the pin 91 extend through slots 99 in the shaft 31 and are adapted for selective engagement in the recesses 94 and upon movement of the rod 96 respectively into its opposite end positions. Detent balls |80, similar to the balls 62, are adapted for engagement in recesses HH and I82 to secure the shifter rod' 96 in its selected positions of adjustment. A plug I03 serves to close the outer end ofthe shaft 31 and the interior of the bearing space may be lubricated through a fitting I04. The inner end of the shifter rod 96 carries a pin I05 which projects through slots I06 in the shaft 31 between the bearing brackets 35. The pin N15 issecured to a clutch collar I01 engaged by a yoke |08 fixed on a shaft I09. This shaft is journaled in the intermediate plate 21 and the front end thereof extends forwardly through the' open-- ing 11 in thedoor 4 and is provided with a hand lever |'|0.

Pivotally -mounted on the lower end of. the depending leg ll of the bracket 9 is a base plate said intermediate plate, I means for .adjustably interconnecting s-aidtop ,plateand said intermethe plate Zland afford means for adjusting the angular position; ofthe" plate I relative to the plate 27.

Rigidlymounted on the undersideof the, base plate III is an electricdrivemotor I18 havinga shaft .9. 1 A double V step pulley I20. is secured to the shaft ,IIB. andais connected through V belts I2I and I22, respective1y,yto the. pulleys 83 and 84. It will be seen that by appropriate. manipulae tion vof the'hand lever III), the clutch shaft 31 may be driven selectively from the electric motor H8 at either one of two different speeds. It will be understood that the belts I9 and 8| may be suitably tensioned by adjusting the intermediate plate 21 relative to the plate I0 and that the tension of the belts I2I and I22 may be similarly tensioned by adjusting the position .of the base plate III relative to the intermediate plate 21.

It will be seen that I have provided a new and advantageous variable speed drive adapted particularly for use as an underdrive for a screw lathe. This drive is fully'housed within the pedestal leg 3 of the lathe and may be conveniently lubricated by use of a grease gun. Although the underdrive itself is enclosed, it may be easily and quickly adjusted from the exterior by the readily accessible hand levers I8 and III).

I claim as my invention: I

1. A drive for a lathe having a spindle, said drive comprising, in combination, a cabinet constituting a leg for said lathe, a bracket structure mounted in said cabinet and having a generally horizontal top plate, a shaft journaled on said top plate, a pulley fixed to said shaft and adapted to be connected through belt means to said spindle, an intermediate plate mounted on said bracket, a clutch shaft journaled on said intermediate plate, two pulleys mounted on one end of saidclutch shaft, two pulleys fixed on said first. mentioned shaft and connected through belts to said pulleys on said clutch shaft, the two sets of pulleys affording two different selective speed drives between said shafts, clutch means for connecting said clutch shaft selectively to said two pulleys thereon, said clutch means having an actuator projecting to the exterior of said cabinet, a base plate mounted on said bracket, an electric drive motor mounted on said base plate and having a motor shaft, a

cone pulley mounted on said motor shaft, two pulleys of unequal size mounted on said clutch shaft in alignment with said cone pulley and connected to said cone pulley by belts, and clutch means for selectively connecting said clutch shaft to said last mentioned pulleys, said clutch means having an actuator extending to the exterior of said. cabinet.

2. A drive for a lathe having a spindle, said drive comprising, in combination, a cabinet constituting a leg for said lathe, a bracket structure pivotally mounted in said cabinet and having a generally horizontal top plate, a first shaft journaled on said top plate, means for adjustably supporting said bracket in different pivotal positions, a lower intermediate plate pivotally mounted on said bracket, a clutch shaft journaled on diate plate in different relative angular positions, a base plate pivotally connected to said bracket, an electric drivemotor mounted on said base plate and having a motor; shaft, means for adjustably interconnecting said intermediate plate and said base plate. in: different relative angular positions, a. selective-speed belt. drive. between said first shaft and said; clutch shaft, and a selective-speed belt. drive. between said clutch shaft and said motor shaft. a

3. A power transmission drive comprising, in combination, a bracket having a mounting plate, a, shaftjournaledon said plate, an intermediate plate pivotally mounted .on said bracket in generally parallel relation to'said' first mentioned plate, .aclutch shaft-journaled on said interme-. diate plate, .a base plate pivotally mounted on said bracket in generally parallel relation to said first mentioned plate, a motor mounted on said base plate and having a motor shaft, a selective speed belt drive connecting said first two mentioned shafts, a selective speed belt drive connecting said clutch shaft and said motor shaft, each of said drives including a clutch, said clutches being associated with said clutch shaft, adjustable means interconnecting said plates to secure them in different selective relative angular positions, and means adapted to transmit power from said first mentioned shaft.

4. 'A power transmission drive comprising, in combination, a bracket structure having a generally horizontal top plate, a shaft journaled on said top plate, a pulley fixed to said shaft and adapted to be connected through belt means to a driven element, an intermediate plate mounted on said bracket, a clutch shaft journaled on said intermediate plate, two pulleys mounted on one end of said clutch shaft, two pulleys fixed on said first mentioned shaft and connected through belts to said pulleys on said clutch shaft, the two sets of pulleys affording two different selective speed drives between said shafts, clutch means for connecting said clutch shaft selectively to said two pulleys thereon, an actuator for said clutch means, a base plate mounted on said bracket, an electric drive motor mounted on said base plate and having a motor shaft, a cone pulley mounted on said motor shaft, two pulleys of unequal size mounted on said clutch shaft in alinement with said cone pulley and connected to said cone pulley by belts, clutch means for selectively connecting said clutch shaft to said last mentioned pulleys, and an actuator for said 7 last mentioned clutch means.

5. A power transmission drive comprising, in combination, a bracket having a mounting plate, a shaft journaled on said plate, means adapted to transmit power from said shaft, an intermediate plate mounted on said bracket, a clutch shaft journaled on said intermediate plate, a base plate mounted on said bracket, a motor mounted on said base plate and having a motor shaft, a selective speed belt drive connecting said first two mentioned shafts, a selective speed belt connecting said clutch shaft and said motor shaft, each of said drives including a clutch associated with said clutch shaft, and an actuator for each of said clutches.

6. A power transmission drive for a driven element comprising, in combination, a support for said driven element, a bracket structure pivotally mounted in said support and having a generally horizontal top plate, a first shaft journaled on said top plate, means for adjustably supporting said bracket structure in different pivotal positions, a lower intermediate plate pivotal mounted on said bracket structure. a clutch shaft journaled on said intermediate plate, means for adjustably interconnecting said top plate and said intermediate plate in different relative angular positions, a base plate pivotally connected to said bracket structure, an electric drive motor mounted on said base plate and having a motor shaft, means for adjustably interconnecting said intermediate plate and said base plate in different angular positions, a selective speed belt drive between said first shaft and said clutch shaft, and a selective speed belt drive between said clutch shaft and said motor shaft.

7. A power transmission drive for a rotary driven element comprising, in combination, a support for said driven element, a bracket pivotally mounted in said support and having a mounting plate, a first shaft journaled on said plate, an intermediate plate pivotally mounted on said bracket in generally parallel relation to said first mentioned plate, a clutch shaft journaled on said intermediate plate, a base plate pivotally mounted on said bracket in generally parallel relation 

